American hybrid cars got their start back in the '80s, when both Japan and the U.S. entered an industry that was just getting started. The name "hybrid" was selected because they run on two different power sources--often at the same time. Contrast that with an electric vehicle or a gasoline only vehicle, which run on only one source.
Hybrid Cars, otherwise known as HEVs (Hybrid Electric Vehicles) started becoming popular in the U.S. simply because people wanted to save money while doing their part to help fight global warming and to help Americans get independent of foreign oil.
American Hybrid Cars Are Not
However, in the process, American hybrids became Japanese-American hybrids. Because the low-quality and low-technology that U.S. automakers were delivering, Japan had an open door to create what is now arguably a Japanese-owned industry.
American auto buyers responded to the influx of vehicles from Japan such as the Toyota Prius by buying so many of these fuel efficient, high quality Japanese vehicles that would go 200,000 miles without a hiccup, that Detroit had no choice but play catch-up.
And play catch-up they tried, but U.S. automakers were not very good at that either. But instead of trying to compete with the Japanese automakers' fanatical dedication to quality and innovative technology - a trait that Detroit NEVER had until recently - American automakers instead did the smart thing and worked WITH the Japan automakers. That's why today nearly every vehicle in the U.S. is a combination ("hybrid" if you will) of Japanese and American technologies:
Look Under The Hood - Japanese Technology
Just open the hood of nearly ANY U.S. car - I'm talking ones that "look" American and have emblems on them like "Buick" or "Pontiac," etc. and what you'll see is a Japanese engine, or at least an American engine heavily influenced by and incorporating Japanese technology.
But that's o.k., because that's just smart marketing and besides, nowadays at least 50% of the profits and jobs for these autos are U.S.-based. And not only that, now Detroit is figuring out how to incorporate hybrid vehicle technology into what used to be gas-guzzling behemoths like Chevy Tahoes and such. Also into fast sports cars.
Detroit is doing this with success because they know that the large majority of Americans would rather have a muscle car and spend a little more on gas than otherwise; hybrids will only become as popular in the U.S. as gas availability and price force them to be. Americans are used to pushing on the accelerator and feeling and hearing POWER.
Some of today's "muscle car hybrids" have big gasoline engines--not the little anemic and much smaller hybrids. But they're highly optimized with variable valve timing and other high-tech gas engine technologies, in addition to having the requisite electric motor too. Matter of fact, some have gas engines 200 hp and more. Some Lexus hybrids have a total of over 350 hp, with 200 hp coming from the gasoline engine alone. Yet they're getting in the low 30's mpg on the highway and they accelerate faster than their big V-8 gasoline-only Lexus models!